Which smart home system is suitable for our new building?

I probably don’t even have the slightest idea of what’s possible with KNX and therefore can’t really assess whether the extra cost would be worth it for us

KNX is the self-driving car. You get in, say "Gothenburg," and it takes you there. But it costs accordingly for the equipment. Radio is the car with driver assistance systems; you have to steer yourself, monitor everything yourself in case the system makes a mistake or doesn’t know what to do because the situation becomes unclear.

Regarding radio outages... you’re not running an industrial production, right? If the TV suddenly turns off unexpectedly or a light switches on/off that wasn’t desired... you can live with that. We’re not talking about a paper machine or glass factory where you would have to discard the day’s production if the system suddenly fails.

In such discussions, everyone usually highlights the advantages of their own solution and the disadvantages of the others. KNX is certainly by far the best solution. But I don’t even want to know what the 45 bus cables to my sockets alone would have cost... and where I would have to put them in the utility room... I probably don’t even have the space for such a cabinet, with a 6.5 m² utility room.

PS: And you must not fall into the belief that this is representative, like “radio in new buildings is a no-go, nobody does that”… yes, I know some neighbors who are building with KNX… but I also know quite a few who built new homes without a single thought about smart home. They don’t even switch a single socket with a radio socket from the hardware store…

ok

a different question about KNX (maybe KNX is no longer relevant because of this anyway)
KNX relies on presence detectors that then control everything

Is it even feasible to implement KNX if you have a large dog weighing 40-50 kg and it is allowed everywhere in the house?
Wouldn't the dog trigger the presence detectors every time?

Does KNX even make sense if you have a large dog, or would it just mess up the automations and constantly turn lights on and off everywhere?

To my knowledge, it can be activated, although I haven't seen it in practice yet, especially whether the child is then recognized or still gropes around in the dark.

But I don’t even want to know how much the 45 bus cables to my sockets alone would have cost...

So you didn’t understand KNX. You don’t lay a bus line to sockets.

Can KNX even be implemented usefully if you have a big dog 40-50 kg and he’s allowed everywhere in the house?
The dog would trigger the presence detectors every time, right?

Does it even make sense to use KNX if you have a big dog or would he just mess up the automations and turn lights on and off everywhere all the time?

No, it will always trigger. You can somewhat counteract this with some very sharply adjusted detectors at switch height. But this has nothing to do with KNX; this happens with every detector from any system.

As far as I know, it can be set, although I have not seen this in practice yet, especially whether the child is recognized or just wandering around in the dark.

Doesn’t work reliably with normal ceiling PDs.

Does the dog always have to live in the dark or is it allowed to turn on the light?

Well, if the dog is slurping at the bowl at night, the hallway light doesn't necessarily have to turn on. But that could be controlled by a timer. And dogs have improved night vision; they usually don't need any light.